I must say it depends on your style of playing the class.
While having pure STR, you deal massive damage resulting to an instant win, though there is a matter of whoever gets to attack first. This is the reality of pure STR.
The downside on being pure STR is being squishy. Because you concentrated on STR you would be low on VIT(HP,DEF) therefore being squishy because your survivability is low.
While having pure VIT, you would have great HP and Defense. For me there really isn't a downside for being VIT though 1 Hit K.O isn't assured.
But most of all, everything relies on EQUIPMENTS.

What i did was pure strength, on both stats and equipments, for the reason that i mostly warred on my AR. I haven't tried doing EVA type because i could imagine how my damage will decrease drastically by doing so.
My path was Voyager->Archer->Rune Walker->Arch Ranger
By following this path i assure you will have a great time dealing massive damage, but you pay the price for being squishy XD
Note: EVA Type should work too but Archers don't get high evas as daggers do but it will still do. So i always have a different set of equipments depending on the given condition on Wars/Grinding XD

Dungeon Dates Resets Daily @ 12:00am and 3:00am (Server Time) or 12:00pm and 3:00pm (PH Time) that means twice a day, it doesn't matter if you're logged in or not it will always reset.
Though it resets twice, doesn't mean you can do 20 dd's in a row, you have to consume all Ten(10) DD's in the first reset so you can do another Ten(10) when it resets at 3:00pm (PH Time).
The question has already been answered a few times.
Closing Thread.

Well if you ask me imo, I would choose Cardi over GM for the reason that i mostly do wars when i hit the right level to. But, GM isn't a bad idea at all since the class has trusty disables(stuns,sleeps,freezes) and its awesome AoE skills for great mobbing conveniency :3